The term synthesis gases refers to gas mixtures which contain hydrogen and carbon oxides and are used in various synthetic reactions. Examples are the synthesis of methanol, the preparation of ammonia by the Haber-Bosch process or the Fischer-Tropsch synthesis.
A widely used process for producing synthesis gases is the autothermal entrained flow gasification of gaseous, liquid or solid fuels, as is described, for example, in DE 10 2006 059 149 B4. At the top of a reactor, an ignition and pilot burner is arranged centrally and three gasification burners are arranged rotationally symmetrically around the reactor axis. Coal dust together with oxygen and steam as gasification agent are fed via the gasification burners into a gasification space of the reactor in which the fuel is converted into synthesis gas. The hot gasification gas leaves the gasification space together with the liquid slag and goes into a quenching space into which water is sprayed in order to cool crude gas and slag. The slag is deposited in the water bath and is discharged via a slag discharge. The quenched crude gas is taken off saturated with water vapour from the quenching space and purified in subsequent purification stages. Since the fuel is reacted directly with the oxidant, oxidant and fuel have to be fed in coaxially or coannularly.
U.S. Pat. No. 5,549,877 A1, too, describes a process and an apparatus for producing synthesis gas, wherein an oxygen-containing oxidant is fed in centrally at the top of the reactor and is introduced together with fuel fed in annularly around the oxidant inlet into the reaction space in which the fuel is firstly reacted substoichiometrically. A flame is formed and this spreads downwards into the reaction space. In a recirculation zone, the materials present in the flame flow back upwards. An additional stream of oxidant is fed into the reaction zone downstream via an annular conduit, so that a larger flame zone is formed.
DE 10 2006 033 441 A1 describes a reformer for a fuel cell system, in which a fuel is introduced into an oxidation zone through a centrally arranged fuel inlet and an oxidant, in particular air, is also introduced via oxidant feed devices provided perpendicularly thereto. Within the oxidation zone, reaction of fuel and oxidant takes place in the form of combustion. The product gas formed then goes downstream into a mixing zone in which fuel and oxidant are additionally introduced by means of a secondary fuel feed device. The product gas mixed with the additional fuel goes into a reforming zone in which it is converted by endothermic reaction into a hydrogen-rich gas mixture which is taken off and made available to a fuel cell stack.
The invention taught in the German first publication DE 10 2010 004 787 A1 relates to the production of synthesis gas by partial oxidation of liquid or gaseous, carbon-containing fuel in the presence of an oxygen-containing oxidant by means of a structurally simple burner, wherein the fuel, the oxidant and a moderator are fed separately to the burner and the fuel and the moderator are mixed in a mixing chamber of the burner before they are brought into contact with the oxidant. In order to reduce the load on the burner, especially during operation with transient conditions, the oxidant is introduced centrally into a combustion chamber through an outlet opening of the burner and the mixture of fuel and moderator is introduced concentrically around the oxidant through the outlet opening into the combustion chamber.
In the types of burner described for synthesis gas production, commencement of the partial oxidation reaction within the actual burner can occur, and the burner therefore has to be cooled by passing a liquid coolant through it. However, in the case of malfunctions in the coolant supply, the burner concerned can fail and an unplanned stoppage of the synthesis gas production plant can thus result.